When it comes to enclosed and underground parking garage ventilation, the effectiveness of the system can profoundly impact the health and safety of occupants. With severe contamination from exhaust gases, CO and NO2, mechanical engineers are tasked with the daunting challenge of keeping the space healthy with proper ventilation.
But safety isn’t the only consideration mechanical engineers must weigh when designing their ventilation systems. From energy efficiency to code requirements, each application has unique design needs and challenges.
In North America, code requirements according to the International Mechanical Code (IMC) and ASHRAE stipulate that garage ventilation systems run continuously while occupants are present to ensure a safe environment. These codes outline specific ventilation rates and sometimes varying based on local jurisdiction. Sweep ventilation systems are part of an effective design strategy but oftentimes additional solutions are required to optimize performance.
“It’s easy to move the correct volume of air specified by the codes,” explains John Gramke, National Sales Manager of Commercial Car Park Ventilation at Systemair. “The challenge is how to mix, dilute and evacuate the contaminated air in an effective and efficient manner.”
There are a number of additional challenges posed by traditional car park ventilation systems:
1) Traditional ventilation systems do not induce much airflow from a distance
2) Air cannot reach all areas within the car park, resulting in “dead zones” and “hot spots”
3) Supply and exhaust fans require longer run-time to be code compliant, compromising energy efficiency
4) The effective life of gas monitoring systems is often reduced
For years, engineers and designers have recognized these challenges and the need for a solution. A convenient remedy emerged in which commercial box fans or stationary cooling fans are used to circulate air.
However, this method is ultimately an ineffective answer to a very real challenge. Not only do these fans induce little air, but they also have a very limited throw distance. Additionally, a large number of fans are required to cover even minimal areas.
“Typically, we find engineers either include way too many of these traditional garage circulating fans in their project design or way too few,” says Gramke. “Because they are not designed for the application, there is no real way of quantifying their effectiveness.”
Unlike commercial box fans or stationary cooling fans, Induction Jet Fans are designed specifically for the ventilation of underground and enclosed parking garages.
High Induction Jet Fans produce a relatively high discharge velocity that causes the discharge air to collide with the air in front of the fan, thrusting the air forward. Simultaneously, the friction created draws the surrounding air along with it, resulting in the induction effect that moves the surrounding air in the direction of the airflow.
Above: Layout of induction jet fans in underground garage application.
The induction effect ensures that the quantity of air in motion will always be considerably larger than the quantity of air passing through the fan itself. As a result, the air volume induced will be many times greater than the fans airflow rating.
When installed, induction jet fans are strategically placed at particular points within the car park to both improve airflow and also save space.
No matter the specifications of your underground or enclosed car park, induction jet fans offer several key advantages over traditional ventilation systems:
1) Space-Saving:Induction jet fans are ideal for spaces with low ceiling heights or limited space.
2) Energy Efficiency: Unlike traditional solutions, induction jet fans are controlled by gas detection. This enables the code-compliant SA and EA fans to operate more efficiently, reducing energy consumption.
3) Flexible Design: Flexibility of the fan positioning and exhaust shaft location make induction jet fan systems a particularly effective solution for renovations and new construction options.
4) Cost savings: With no ducting required, induction jet fans allow you to cut costs associated both with materials and installation time.
5) All-over Ventilation: Induction jet fans thrust air throughout the entire structure, allowing effective air mixing and eliminating “dead zones.” This also ensures that air reaches every corner of the car park, reducing the risk of CO accumulation.
Explore Systemair’s selection of induction jet fan solutions and contact our experts to find a solution tailored to your project needs.
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